strong petrol smell and chuffing sound!!

Hi, my S2a has recently developed a nasty fumey smell, I have a weber 34 ICH, and have a service kit, which I will use soon, but also there seems to be a chuffing sound, when I release the revvs, like downhill, sounds like a train!! In my imagination, I picture unburned fuel perhaps? like almost a backfire... I hope the service of the carb will do it, but is there any other likely reason for this? cheers.

Tumbleweed!! ?

Sounds like an air leak somewhere and the carb is a good place to start. Check the carb to manifold joint and the manifold to block joint. It could just be a misfire so check the spark plugs look OK and the timing is correct. Of course it could be something more serious, but check the more obvious stuff first.

ThankS. I will get a chance tomoro to get cArb off and check. Luckily not driving much at the mo.

Seems like manifold, ordered new one. Got to brave the trying to get old one off now! Have been soaking the nuts with copper grease for a week or so, while I wait for the parts. has made me get gas again, to avoid the noxious fumes when driving! Also got Ss exhaust s/hand so will fit at same time.

Plus gas is good for rusty nuts.
Warm it up first.
If you can get access a nut splitter might do the trick.

Cheers was trying to remember what that stuff was called! My brother used to rave about it when he had a bike. Will get some in.